Rufus, demonstrating where Jenny gets her occasional moments of being a dipshit, is actually trying to explain to Alison how she's not "overreacting per se, just having a reaction that is above and beyond what is appropriate." Which is not at all untrue in any way, but is dumb to say. Nobody ever heard that shit and went, "You know what? You're right. My feelings at this moment are not valid." Alison whines about how she's been cooking and looking at people with her big beady eyes very intensely in an attempt to somehow make up for ditching them and fucking around on him, only to find out that Rufus has been "making out at theme parties," and Lily's like, "Come on, we didn't make out, and also it was a ruse to convince this gay rapist kid's creepy father that we were... Actually, I don't even remember why we made out. And by 'made out,' I mean 'barely even kissed.'" Before Alison can even get her head around the real deal here, which is that she's right by being wrong, because Rufus + Lily 4EVA, even if they haven't acted on it, Serena comes walking back in with Blair, and immediately A) notes the totally weird vibe, and B) goes looking for Dan, with Blair in tow. Man, I thought having Lily in the DUMBO loft was weird, but now Blair? It's like looking at an Escher painting. It's like Roger Rabbit!
Dan's praying none of them are related, and Jenny points out that Eric's hair is naturally dark brown, "kind of Rufus-like," but before anybody can ask why, then, a fourteen-year-old boy who is a member of neither a boy band nor the touring company of Love! Valor! Compassion! requires such intense highlights, Serena enters, freaking Dan out with Blair's presence. "Explanation to follow, but first, what's going on with our parents?" Jenny gets her up to speed on the parental dating, and Dan explains they're not related -- "Ignore my roots," Eric helpfully suggests -- and Blair points out that, porny Brady Bunch effect or no, Dan and Jenny totally have a garage door in the middle of their room. She then notices Cedric the Cabbage Patch Kid in the corner, and says hello. Dan tries to smother himself with a pillow, and Serena probes deep enough to hear about how their parents totally had sex. "She was a groupie, and he was Almost Famous." Blair realizes that this makes her the product of the healthiest family in attendance, or on this show, and then Serena and Dan shepherd the group out through the fire escape to go get some food untainted by incest.